There is currently known in the prior art a wide variety of bicycles which include shock absorbing rear assemblies. Such bicycles typically include a main frame which comprises an elongate top tube rigidly secured to and extending between a head tube and an elongate seat tube. The head tube provides a structural base for the stem of the bicycle which has the handlebars attached thereto. The seat tube itself provides a base for a seat post which is generally telescopically received thereinto and to which is secured the saddle or seat of the bicycle. In the main frame, the seat tube includes a generally cylindrical bottom bracket shell attached to the bottom end thereof. The bottom bracket shell accommodates the crank assembly of the bicycle. The crank assembly itself comprises a bottom bracket spindle which includes a pair of cranks and a chain wheel attached thereto. Rigidly secured to and extending between the head tube and the bottom bracket shell is an elongate down tube of the main frame.
The shock absorbing rear assemblies of the prior art bicycles take on a wide variety of different configurations. In one commonly used configuration, the rear assembly comprises a pair of chain stays, the front ends of which are pivotally connected to the main frame. The back ends of the chain stays are attached to respective ones of a pair of drop-outs which accommodate the axle of the rear wheel. Also attached to respective ones of the drop-outs are the bottom ends of a pair of seat stays or swingarms, the top ends of which are attached to one end of a shock absorber. The end of the shock absorber opposite that attached to the swingarms is itself attached to a portion of the main frame. Typically, the shock absorber is disposed within the interior of the main frame (i.e., within the triangle defined by the top, seat and down tubes), with the end thereof opposite that attached to the swingarms being attached to the top tube. When the rear wheel encounters a bump or other obstruction, the resultant upward travel of the rear wheel axle is effectively dampened by the compression of the shock absorber.
As previously indicated, the above-described rear assembly is exemplary only, in that many variations of shock absorbing rear assemblies exist in the prior art. The common characteristics of all shock absorbing rear assemblies is that they include the rear wheel rotatably connected thereto and are movable independently of the main frame for purposes of facilitating the actuation of the shock absorber and the dampening of the upward movement of the rear wheel.
Those prior art bicycles including shock absorbing rear assemblies possess certain deficiencies which detract from their overall utility. Foremost of these deficiencies is the placement of the shock absorber of the rear assembly relative to the main frame of the bicycle. In this respect, in most prior art bicycles including shock absorbing rear assemblies, the shock absorber has an elevated position relative to the main frame and extends either completely or partially within the front triangle defined thereby. The elevated position of the shock absorber raises the center of gravity of the bicycle, thus diminishing its handling and performance characteristics. Additionally, the complete or partial placement of the shock absorber within the interior of the main frame increases the complexity and hence the cost associated with the manufacture and assembly of the bicycle.
The present invention addresses and overcomes these deficiencies by providing a bicycle including a shock absorbing rear assembly, the shock absorber of which is removed from within the interior of the main frame and does not load the seat tube or down tube thereof. The construction of the present bicycle significantly lowers the center of gravity thereof by lowering the position of the shock absorber relative to the main frame. This lower center of gravity substantially enhances the handling and performance characteristics of the present bicycle, and further provides various efficiencies in the assembly thereof, thus reducing the associated manufacturing costs.